Research And Implementation Of Dual-mode Dual-band Independently Reconfigurable Substrate Integrated Waveguide Filter

The increasingly crowded spectrum of wireless communications has greatly stimulated the demand on the multifunctional and frequency-agile transceiver systems in microwave/millimeter wave/terahertz bands.Simultaneously,the features of low cost,low power consumption,easy integration and miniaturization of microwave devices for wireless communication technology are required.Considering that substrate integrated waveguide(SIW)combines the advantages of waveguides and microstrip lines,such as high quality factor,large power capacity,small size and easy integrated,a large amount of research has been made on the SIW for the millimeter wave band.As one of the key modules of the wireless system,two novel dual-band reconfigurable filters are proposed on the basis of the SIW technology in this thesis.The primary research work and results are summarized as follows.(1)A dual-band dual-mode SIW Filters with independently reconfigurable TE101 resonant mode is designed.A novel perturbation approach is proposed,using additional metalized for implementing the dual-band or wide-band dual-mode SIW filters with a fixed or an independently reconfigurable low-frequency band.The low-frequency and the high-frequency bands are generated by the TE101 and the TE102 modes,respectively.Finally,the measured results indicate that the available frequency-ratio(fR)ranging from 1 to 1.3 can be realized by four two-cavity dual-band SIW filters.The center frequency of the lower passband can be tuned from 4.61 GHz to 5.24 GHz with a range of 12.8%,whereas the center frequency of the higher one is fixed at around 6.18 GHz for the SIW filter with four reconfigurable states via-holes.(2)A novel independently reconfigurable dual-mode dual-band SIW filter is designed.The lower passband is independently tuned by changing the connection state of the perturbation via-holes to the top metal-layer and the lengths of the interference slot in each cavity.While the independent control of the upper passband only depends on changing the lengths of the interference slot.The result showed that the dual-band SIW filter not only has af fR ranging from 1.14 to 1.58.but also can be considered as a single passband one with a tunable range of 40.5%from 1.26 GHz to 2.12 GHz.(3)A dual-mode dual-frequency SIW filter with "H" type perturbation is designed.A perturbation method combining the perturbation via-holes with the interference slot is proposed.At the same time,the degree of the influence on the electromagnetic distributions of the TEioi and the TE102 modes will vary in the number of the perturbation via-holes.But it does not cause a leakage of the electromagnetic energy the resonance modes.Finally,the simulated results on several filters with the same size showed that the lower passband moves independently with a range of 11.7%and the higher passband moves independently with a range of 8.5%.